Spark plug



Oct. 16, 1934. .L c. BRAND 1,977,038

SPARK PLUG Filed June l5,

f1 1 R 5M Q WML o* @www Patented Oct. 16, 1934 UNITED STATES PATENT OFFICE 1 Claim.

My invention relates to spark plugs of the kind especially designed for use in high compression cylinders.

One of my objects is the provision of a spark 5 plug having a spark gap within the socket of the shell and at the point of greatest efficiency within the socket.

Another of my objects is the provision of a spark plug having a spark gap positioned appreciably within the socket and so arranged that the electrodes may be readily adjusted for increasing or decreasing the space between the electrodes.

Another of my objects is the provision of a ground electrode which is inclined from the mouth of the shell toward the axial center thereof and toward the interior of the socket.V

A very important object of the invention is the provision of a ground electrode which is anchored in the shell of the spark plug by the distortion of the metal of the shell and of the electrode.

Having in View these objects and others which will be pointed out in the following description, I will now refer to the drawing, in which Figure 1 is a View partly in elevation of the entire spark plug. and partly in section of the shell, the washer, and gasket, the gure being drawn to an enlarged scale.

Figure 2 is a view showing the lower end por- 30 tion of the shell, partly in elevation and partly in section, showing a modication of myY invention, the View being drawn to a greatly enlarged scale in order to more clearly disclose the anchor for the ground electrode.

The spark plug as shown includes a shell 10, a core 11 of stone or porcelain or other dielectric, a nut 12 and a gasket 13. The core 11 is provided with an annular shoulder 14 which is tightly held between the nut 12 and the gasket 13. 40 The central electrode 15 passes through the core 11 and terminates at its upper extremity in a screw threaded portion for receiving the nut 16. As thus far described the structure is Well known, being common to spark plugs of many types.

In the present instance instead of the electrode 15 extending to within close proximity of the mouth of the shell 10, the electrode is shortened to bring its extremity into a position of maximum efciency of the spark gap in high compression cylinders. The ground electrode 17 then approaches the electrode 15 from near the mouth of the shell 10 passing first in an inclined direction toward the center of the spark plug and away from the mouth of the shell, the direction being then changed abruptly so as to approach the electrode 15 at an angle more nearly approaching a right angle.

In anchoring the electrode 17 in the shell 10, I rst drill an aperture through the shell wall in very close proximity to the rim of the mouth (Cl. 12S- 169) of the shell 10. This aperture is of a diameter to snugly receive the electrode 17 and it is positioned not only in close proximity to the mouth but also below the end of the screw threaded portion of the shell 10. When the electrode has been inserted in the aperture thus formed, a center punch is applied at the point 18 and is given a sharp blow which distorts the metal of the shell l0 and the electrode 17. This then provides an anchor for the electrode 17 which will hold the electrode in place regardless of the heat fluctuations in the spark plug. Neither the ooncussions of the explosions nor any ordinary mechanical blows can loosen an electrode which is thusv anchored in the shell.

The anchor shown in Figure 1 may be modied as shown in Figure 2. In this case the socket in .the rim of the shell 10 takes the place of the aperture in the shell 10. The electrode 17 is then inserted at its free end in the socket thus formed so that its spark extremity is in the proper relation of the electrode 15. The center punch is then driven against the point 18 to compress and distort the metal of both the shell 10 and the electrode 17'.

The construction in both cases not only pro. vides a iirm and secure anchor for the ground electrode but it leaves the two electrodes in such relative positions that they may be easily adjusted for increasing or decreasing the length of the spark. If greater separation is required, a screw driver inserted between the two points may be used for spreading the points. If it is desired to bring the two points closer together, all that is necessary is to introduce the screw driver between the electrode 17 and the shell wall and to thus force the electrode 17 toward the electrode 15.

Having thus described my inventionrin such full, clear, and exact terms that its construction and operation will be readily understood by others skilled in the art to which it pertains, what I claim as new and desire to secure by Letters Patent of the United States is:

A spark plug comprising a shell, an electrode positioned centrally Within the shell and insulated therefrom and terminating at its inner end inwardly of the inner end of the shell, and a second electrode secured at one end to the inner end of the shell and extending sharply inwardly of the shell and terminating at its inner end in an extension extending in the direction of the inner end of said rst electrode and disposed at substantially right angles toV said first electrode.

` JAMES C. BRAND. 

